package dame;

import java.util.List;

public class MyLinkedList implements IList{
    static class ListNode{
        public int val;
        public ListNode prev;
        public ListNode next;

        public ListNode(int val) {
            this.val = val;
        }
    }
    public ListNode head;
    public ListNode last;

    @Override
    public void addFirst(int data) {  //头插法
        ListNode node = new ListNode(data);
        if (head ==null){
            head = last = node;
        }else {
            node.next = head;
            head.prev = node;
            head = node;
        }
    }

    @Override
    public void addLast(int data) { //尾插法
        ListNode node = new ListNode(data);
        if (head ==null){
            head = last = node;
        }else {
            last.next  =node;
            node.prev = last;
            last = last.next;
        }
    }
    public void Llist(int index) throws Iempty{
        int len  = size();
        if (index<0||index>len){
            throw new Iempty("index位置不合法");
        }
    }
    private ListNode FindNode(int index){  //查找index位置的cur
        ListNode cur = head;
        while (index !=0){
            cur  =cur.next;
            index--;
        }
        return cur;
    }
    @Override
    public void addIndex(int index, int data) { //任意位置插入
        try {
            Llist(index);
        }catch (Iempty e){
            System.out.println("index 位置不合法");
            e.printStackTrace();
        }
        if (index ==0){
            addFirst(data);
        }
        if (index==size()){
            addLast(data);
        }
        ListNode node = new ListNode(data);
        ListNode cur = FindNode(index);
        node.next = cur;
        cur.prev.next = node;
        node.prev = cur.prev;
        cur.prev = node;
    }

    @Override
    public boolean contains(int key) {
        ListNode cur = head;
        while (cur != null){
            if (cur.val==key){
                return true;
            }
            cur = cur.next;
        }
        return false;
    }

    @Override
    public void remove(int key) { //删除key
        ListNode cur = head;
        while (cur != null){
            if (cur.val==key){
                if (cur==head){
                    head = head.next;
                    if (head != null){
                        head.prev = null;
                    }
                }else {
                    cur.prev.next = cur.next;
                    if (cur.next == null){
                        last  =last.prev;
                    }else {
                        cur.prev.next  =cur.prev;
                    }
                }
                return;
            }
            cur  =cur.next;
        }
    }

    @Override
    public void removeAllKey(int key) {    //删除所有的key
        ListNode cur = head;
        while (cur != null){
            if (cur.val==key){
                if (cur==head){
                    head = head.next;
                    if (head != null){
                        head.prev = null;
                    }
                }else {
                    cur.prev.next = cur.next;
                    if (cur.next == null){
                        last  =last.prev;
                    }else {
                        cur.prev.next  =cur.prev;
                    }
                }
            }
            cur  =cur.next;
        }
    }

    @Override
    public int size() {  //求链表长度
        int len  =0;
        ListNode cur = head;
        while (cur != null){
            len++;
            cur = cur.next;
        }
        return len;
    }

    @Override
    public void clear() {     //清空链表
        ListNode cur = head;
        while (cur !=null){
            ListNode curN = cur.next;
            cur.prev = null;
            cur.next = null;
            cur = curN;
        }
        head = last = null;
    }

    @Override
    public void display() {  //打印链表
        ListNode cur = head;
        while (cur !=null){
            System.out.print(cur.val + " ");
            cur = cur.next;
        }
        System.out.println();
    }
}
